Basic algorithm

coder3112 · coder3112 · commit 24684852735f · 2025-06-26T17:25:50.000+02:00
diff --git a/factoradic.py b/factoradic.py
@@ -0,0 +1,36 @@
+import argparse
+import math
+
+
+def dec_to_fact(n: int) -> int:
+    """Refer tp XKCD 2835."""
+    fact = 1
+    i = 1
+    while fact < n:
+        i += 1
+        fact = math.factorial(i)
+    if fact == n:
+        largest_base, largest_fact = i, fact
+    else:
+        largest_base = i - 1
+        largest_fact = math.factorial(largest_base)
+
+    leading_digit = math.floor(n / largest_fact)
+    leading_digit_padded = int(str(leading_digit) + "0" * (largest_base - 1))
+    full_number = leading_digit_padded
+
+    total_n_found_so_far = leading_digit * largest_fact
+    if total_n_found_so_far == n:
+        return full_number
+    return full_number + dec_to_fact(n - total_n_found_so_far)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("value")
+
+    args = parser.parse_args()
+    decimal = int(args.value)
+
+    factoradic = dec_to_fact(decimal)
+    print(factoradic)
